The present invention relates to a large size display apparatus for a video signal adapted for a high definition television (HDTV) system which has scanning lines twice as large in number as the scanning lines of a conventional television (TV) system and a wide aspect ratio. More particularly, the present invention is concerned with a large size display apparatus for an HDTV system, which forms a wide screen by use of a plurality of video monitors, video projectors or similar display units of an conventional TV system.
An HDTV system with the above-mentioned advanced features has a resolution comparable with that of a 35 millimeter film and is applicable to various industrial fields such as electronic publishing and film production. Especially, high definition of the HDTV system allows a picture to be displayed on a wide screen with a minimum of degradation and, therefore, promises the applicability of such a system to a large sized display.
A Hi-Vision system developed by NHK in Japan is a specific form of the HDTV system and has 1125 scanning lines in a frame, sixty fields per second, and an aspect ratio of 16:9. While the following description will concentrate on the Hi-Vision system which is most advanced regarding practical use, the present invention is of course easily applicable to any other HDTV systems.
State-of-the-art displays used for a Hi-Vision video signal are CRTs (Cathode Ray Tube) and video projectors. The maximum size of CRTs currently on the market is about 40 inches. Although video projectors may have greater sizes than CRTs, the former is inferior to the latter when it comes to the picture quality and stability, e.g., resolution, dynamic range and luminance as well as to the cost. Thus, it is difficult to provide a large size display making the most of the picture quality particular to the Hi-Vision system at low cost.